Server and method for aligning part of product with reference object

ABSTRACT

In a method for aligning a part of a product (moving object) with a reference object, triangle data of the moving object is acquired, and feature elements of the moving object is fitted according to the triangle data. Feature elements of the reference object which match the feature elements of the moving object are determined, and the moving object is moved from a position of a center point of the feature elements of the moving object to a position of a center point of the matched feature elements of the reference object. A moving-and-rotating matrix of the moving object is obtained according to Quasi-Newton methods, and the moving object and the reference object are aligned by moving and rotating the moving object according to the moving-and-rotating matrix.

BACKGROUND

1. Technical Field

Embodiments of the present disclosure generally relate to productmeasurement technology, and particularly to a server and a method foraligning a part of a product with a reference object.

2. Description of Related Arts

In automated processes, a product on a production line should becarefully measured. A computer can check feature elements of the productto ensure that quality of the product is within predeterminedtolerances. During measurement of a part of a product, aligning the partof the product with a reference object is an important process. However,it is difficult to exactly and quickly align the part of the product andthe reference object.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of one embodiment of a test server.

FIG. 2 is a schematic diagram of one embodiment of a movement object anda reference object.

FIG. 3 is a block diagram of one embodiment of function modules of analignment unit.

FIG. 4 is a flowchart of one embodiment of a method for aligning a partof a product with a reference object.

FIG. 5A is a schematic diagram of one embodiment of triangle data of themoving object.

FIG. 5B is a schematic diagram of one embodiment of sides which are notshared by the triangles in FIG. 5A.

FIG. 6 is a schematic diagram of one embodiment of a reference figure.

FIG. 7 is a schematic diagram of one embodiment of feature elements ofthe moving object and matching feature elements of the reference object.

FIG. 8 is a schematic diagram of one embodiment of a maximum space boxand a center point of the maximum space box.

FIG. 9 is a schematic diagram of one embodiment of the moving objectafter moving according to an initial moving matrix.

FIG. 10 is a schematic diagram of one embodiment of the moving objectand the reference object after aligning.

FIG. 11 is a flowchart detailing one embodiment of step S18 in FIG. 4.

DETAILED DESCRIPTION

The disclosure, including the accompanying drawings, is illustrated byway of examples and not by way of limitation. It should be noted thatreferences to “an” or “one” embodiment in this disclosure are notnecessarily to the same embodiment, and such references mean “at leastone”.

In general, the word “module”, as used herein, refers to logic embodiedin hardware or firmware, or to a collection of software instructions,written in a programming language. One or more software instructions inthe modules may be embedded in hardware, such as in an erasableprogrammable read only memory (EPROM). The modules described herein maybe implemented as either software and/or hardware modules and may bestored in any type of non-transitory computer-readable medium or otherstorage device. Some non-limiting examples of non-transitorycomputer-readable media include CDs, DVDs, BLU-RAY, flash memory, andhard disk drives.

FIG. 1 is a schematic diagram of one embodiment of a test server 1(e.g., an electronic device). In the embodiment, the test server 1includes an alignment unit 10, a storage unit 20, and a processor 30.The test server 1 is electrically connected to a test device 2. The testdevice 2 measures products, such as a product 40 (e.g., a mobile phonecase), for example.

The alignment unit 10 aligns a part of the product 40 (hereinafter, thepart of the product 40 is referred as “moving object”) with acorresponding part of reference object. The reference object is athree-dimensional design drawing of the product 40 or a scanned image ofa sample of the product 40. The moving object is a scanned image of thepart of the product 40. For example, in FIG. 2, an image in the upperright corner is the moving object 41, and an image on the left is thereference object 42.

In one embodiment, the alignment unit 10 may include one or morefunction modules (as shown in FIG. 3). The one or more function modulesmay comprise computerized code in the form of one or more programs thatare stored in the storage unit 20, and executed by the processor 30 toprovide the functions of the alignment unit 10. The storage unit 20 is adedicated memory, such as an EPROM or a flash memory.

FIG. 3 is a block diagram of one embodiment of the function modules ofthe alignment unit 10. In one embodiment, the alignment unit 10 includesan input module 100, a fitting module 200, a match module 300, aposition module 400, an iteration module 500, and a rotation module 600.A detailed description of the functions of the modules 100-600 is givenbelow in the description regarding FIG. 4.

FIG. 4 is a flowchart of one embodiment of a method for aligning a partof a product with a reference object. Depending on the embodiment,additional steps may be added, others removed, and the ordering of thesteps may be changed.

In step S10, the input module 100 inputs a moving object and a referenceobject. The input module 100 may read the moving object and thereference object from the storage unit 20, or receive the moving objectfrom the test device 2 to input the moving object and the referenceobject.

In step S12, the fitting module 200 acquires triangle data of the movingobject (as shown in FIG. 5A), and fits feature elements of the movingobject according to the triangle data. In detail, the fitting module 200reads all of the triangle data and extracts sides of the triangles inthe triangle data that are not shared by the triangles (as shown in FIG.5B). Then, the fitting module 200 reads points of the extracted sides,and fits the points into the feature elements of the moving object.

In the embodiment, the triangle data is created according to point clouddata in the scanned image of the part of the product 40. The steps ofcreating the triangle data are as follow: constructs a cubical quadcontaining all the point cloud data; constructs a circumscribedtetrahedron around the cubical quad; inserts each point of the pointcloud into the tetrahedron according to three-dimensional coordinates ofeach point, and draws a line to connect each point in the tetrahedronwith each vertex of the tetrahedron.

In the embodiment, the points can be fitted into lines, planes, circles,columns, tapers, and spheres, for example. As shown in FIG. 6, ifdistances between the points and a reference figure (e.g., a referencecircle) are less than a fitting tolerance, a figure fitted according tothe points (e.g., a fitted circle) is the feature element of the movingobject. It is understood that in other embodiments, the moving objectmay not be fitted into a fitted figure, the feature elements of themoving object are sides of the moving object.

In step S14, the match module 300 matches the feature elements of themoving object and feature elements of the reference object. In detail,the match module 300 reads a feature element list of the referenceobject from the storage unit 20, compares the feature elements of themoving object and the feature elements of the reference object, andextracts feature elements of the reference object which match with thefeature elements of the moving object (hereinafter, the extractedfeature elements are referred as “matched feature elements”).

For example, if the feature elements of the moving object and thefeature elements of the reference object both contain three circles,such as if diameters of the three circles are 3 mm, 4 mm, and 4.5 mm, adistance between the 3 mm circle and the 4 mm circle is 8 mm, a distancebetween the 3 mm circle and the 4.5 mm circle is 9 mm, and a distancebetween the 4 mm circle and the 4.5 mm circle is 10 mm, the threecircles of the reference object are regarded as matching with the threecircles of the moving object. As shown in FIG. 7, there are threecircles in the moving object 41, and also three circles in the referenceobject 42, which has the same sizes and position relations with thethree circles in the moving object 41, so the three circles in thereference object 42 are regarded as matching with the three circles inthe moving object 41.

In step S16, the position module 400 moves the moving object from aposition of a center point of the feature elements of the moving objectto a position of a center point of the matched feature elements. Indetail, the position module 400 creates a first maximum space box forthe feature elements of the moving object and a second maximum space boxfor the matched feature elements. The first maximum space box is createdby determining a maximum coordinate value and a minimum coordinate valueof the feature elements of the moving object in an x-axis, a y-axis, anda z-axis of a coordinate system. The second maximum space box is createdby determining a maximum coordinate value and a minimum coordinate valueof the matched feature elements in the x-axis, the y-axis, and thez-axis of the coordinate system.

In one embodiment, a function of the first maximum space box is:boxMov(pt1Min.x, pt1Min.y, pt1Min.z, pt1Max.x, pt1Max.y, pt1Max.z),where pt1Min.x, pt1Min.y, pt1Min.z represent the minimum x, y, zcoordinate values of the feature elements of the moving object, andpt1Max.x, pt1Max.y, pt1Max.z represent the maximum x, y, z coordinatevalues of the feature elements of the moving object.

A function of the second maximum space box is: boxRef(pt2Min.x,pt2Min.y, pt2Min.z, pt2Max.x, pt2Max.y, pt2Max.z), where pt2Min.x,pt2Min.y, pt2Min.z represent the minimum x, y, z coordinate values ofthe matched feature elements, and pt2Max.x, pt2Max.y, pt2Max.z representthe maximum x, y, z coordinate values of the matched feature elements.

The position module 400 calculates an initial iteration parameter,obtains an initial moving matrix of the moving object, and moves themoving object from the position of the center point of the featureelements of the moving object to the position of the center point of thematched feature elements, according to the initial moving matrix. Theinitial iteration parameter is calculated according to positions of acenter point of the first maximum space box and a center point of thesecond maximum space box. As shown in FIG. 8, the cuboid is the firstmaximum space box for the feature elements of the moving object, and thepoint in the center of the cuboid is the center point of the firstmaximum space box.

The initial iteration parameter is an array which contains P[0]-P[5] asfollows:

P[0]=CenMov[0]-CenRef[0], where CenMov[0] is a coordinate value of thecenter point of the first maximum space box in the x-axis, CenRef[0] isa coordinate value of the center point of the second maximum space boxin the x-axis;

P[1]=CenMov[1]-CenRef[1], where CenMov[1] is a coordinate value of thecenter point of the first maximum space box in the y-axis, CenRef[1] isa coordinate value of the center point of the second maximum space boxin the y-axis;

P[2]=CenMov[2]-CenRef[2], where CenMov[2] is a coordinate value of thecenter point of the first maximum space box in the z-axis, CenRef[2] isa coordinate value of the center point of the second maximum space boxin the z-axis;

P[3], which is an angle of the x-axis with a line of the center point ofthe first maximum space box and the center point of the second maximumspace box;

P[4], which is an angle of the y-axis with a line of the center point ofthe first maximum space box and the center point of the second maximumspace box; and

P[5], which is an angle of the z-axis with a line of the center point ofthe first maximum space box and the center point of the second maximumspace box.

P[0], P[1], and P[2] make up the initial moving matrix of the movingobject. As shown in FIG. 9, the moving object 41 is moved according tothe initial moving matrix.

In step S18, the iteration module 500 obtains a moving-and-rotatingmatrix of the moving object according to Quasi-Newton methods. Adetailed description is given below in the description regarding FIG.11.

In step S20, the rotation module 600 aligns the moving object and thereference object by moving and rotating the moving object according tothe moving-and-rotating matrix. As shown in FIG. 10, the moving object41 and the reference object 42 are aligned.

FIG. 11 is a flowchart detailing one embodiment of step S18 in FIG. 4.

In step S100, the iteration module 500 obtains the initial iterationparameter.

In step S102, the iteration module 500 calculates a value of aniteration function f(x):

${{f(x)} = \sqrt{\frac{\sum\limits_{i = 1}^{n}\; \left( \sqrt{\left( {X_{2} - X_{1}} \right)^{2} + \left( {Y_{2} - Y_{1}} \right)^{2} + \left( {Z_{2} - Z_{1}} \right)^{2}} \right)^{2}}{n}}},$

where n is a total number of the points in the feature elements of themoving object; X₂, Y₂, and Z₂ are current coordinate values of thepoints in the feature elements of the moving object in the x-axis, they-axis, and the z-axis; X₁, Y₁, and Z₁ are coordinate values of pointsin the matched feature elements of the reference object in the x-axis,the y-axis, and the z-axis.

In step S104, the iteration module 500 determines whether the value ofthe iteration function f(x) is less than a preset minimum value FunX. Ifthe value of the iteration function f(x) is less than FunX, step S114 isimplemented. If the value of the iteration function f(x) is not lessthan FunX, step S106 is implemented.

In step S106, the iteration module 500 calculates a descent direction ofthe moving object at a current position. In detail, if the value of f(x)after the moving object moving a step (e.g., a preset distance D) at adirection is less than the value of f(x) before the movement, thedirection is the descent direction of the moving object at the currentposition, then the moving object moves a next step at the direction. Ifthe value of f(x) after the moving object moving a step at a directionis not less than the value of f(x) before the movement, the direction isnot the descent direction of the moving object at the current position,then the moving object moves a next step at another direction.

In step S108, the iteration module 500 determines whether the movingobject has a descent direction. If the moving object has the descentdirection, step S110 is implemented. If the moving object has no descentdirection, step S114 is implemented.

In step S110, the iteration module 500 moves the moving object with thedistance D at the descent direction, and calculates a value of aniteration function f(x+1) after the movement.

In step S112, the iteration module 500 determines whether the value off(x+1) is less than the value of f(x). If the value of f(x+1) is lessthan the value of f(x), returns to step S110. If the value of f(x+1) isless than the value of f(x), returns to step S106, and calculates a newdescent direction of the moving object.

In step S114, the iteration module 500 calculates a current iterationparameter. The current iteration parameter is an array which containsPara[0]-Para[5] as follows:

Para[0], a distance between each point in the feature elements of themoving object at current position and the x-axis;

Para[1], a distance between each point in the feature elements of themoving object at current position and the y-axis;

Para[2], a distance between each point in the feature elements of themoving object at current position and the z-axis;

Para[3], an angle of the x-axis with a line of each point in the featureelements of the moving object at current position and correspondingpoint in the matched feature elements of the reference object;

Para[4], an angle of the y-axis with a line of each point in the featureelements of the moving object at current position and correspondingpoint in the matched feature elements of the reference object; and

Para[5], an angle of the z-axis with a line of each point in the featureelements of the moving object at current position and correspondingpoint in the matched feature elements of the reference object.

In step S116, the iteration module 500 obtains the moving-and-rotatingmatrix “Matrix” of the moving object. Matrix=Move*(Move2*(Mat*moveX1)),where:

${{Mat} = {{Move}\; 1*{MatX}*{MatY}*{MatZ}}},{{Move} = \begin{pmatrix}1 & 0 & 0 & {{Para}\lbrack 0\rbrack} \\0 & 1 & 0 & {{Para}\lbrack 1\rbrack} \\0 & 0 & 1 & {{Para}\lbrack 2\rbrack} \\0 & 0 & 0 & 1\end{pmatrix}},{{{Move}2} = \begin{pmatrix}1 & 0 & 0 & {- {{Center}\lbrack 0\rbrack}} \\0 & 1 & 0 & {- {{Center}\lbrack 1\rbrack}} \\0 & 0 & 1 & {- {{Center}\lbrack 2\rbrack}} \\0 & 0 & 0 & 1\end{pmatrix}},{{{moveX}\; 1} = \begin{pmatrix}X_{1} \\Y_{1} \\Z_{1} \\1\end{pmatrix}},{{{Move}1} = \begin{pmatrix}1 & 0 & 0 & {{Center}\lbrack 0\rbrack} \\0 & 1 & 0 & {{Center}\lbrack 1\rbrack} \\0 & 0 & 1 & {{Center}\lbrack 2\rbrack} \\0 & 0 & 0 & 1\end{pmatrix}},{{MatX} = \begin{pmatrix}1 & 0 & 0 & 0 \\0 & {\cos ({angleX})} & {- {\sin ({angleX})}} & 0 \\0 & {\sin ({angleX})} & {\cos ({angleX})} & 0 \\0 & 0 & 0 & 1\end{pmatrix}},{{MatY} = \begin{pmatrix}{\cos ({angleY})} & 0 & {\sin ({angleY})} & 0 \\0 & 1 & 0 & 0 \\{- {\sin ({angleY})}} & 0 & {\cos ({angleY})} & 0 \\0 & 0 & 0 & 1\end{pmatrix}},{{{MatZ} = \begin{pmatrix}{\cos ({angleZ})} & {- {\sin ({angleZ})}} & 0 & 0 \\{\sin ({angleZ})} & {\cos ({angleZ})} & 0 & 0 \\0 & 0 & 1 & 0 \\0 & 0 & 0 & 1\end{pmatrix}};}$ and

Center[0], Center[1], and Center[2] are coordinate values of a currentcenter point of the feature elements of the moving object in the x-axis,the y-axis, and the z-axis; angleX=Para[3]*π/180, angleY=Para[4]*π/180,and angleZ=Para[5]*π/180, where it is circumference ratio.

Although certain inventive embodiments of the present disclosure havebeen specifically described, the present disclosure is not to beconstrued as being limited thereto. Various changes or modifications maybe made to the present disclosure without departing from the scope andspirit of the present disclosure.

What is claimed is:
 1. A computer-implemented method being executed by aprocessor of an electronic device, the method comprising: (a) inputtinga moving object and a reference object; (b) acquiring triangle data ofthe moving object, and fitting feature elements of the moving objectaccording to the triangle data; (c) matching the feature elements of themoving object and feature elements of the reference object; (d) movingthe moving object from a position of a center point of the featureelements of the moving object to a position of a center point of thematching feature elements of the reference object; (e) obtaining amoving-and-rotating matrix of the moving object according toQuasi-Newton methods; and (f) aligning the moving object and thereference object by moving and rotating the moving object according tothe moving-and-rotating matrix.
 2. The method as claimed in claim 1,wherein step (b) further comprises: extracting sides of triangles in thetriangle data that are not shared by the triangles in the triangle data;reading points of the extracted sides; and fitting the points into thefeature elements of the moving object.
 3. The method as claimed in claim1, wherein step (c) further comprises: reading a feature element list ofthe reference object from a storage unit of the electronic device;comparing the feature elements of the moving object and the featureelements of the reference object; and extracting feature elements of thereference object which match with the feature elements of the movingobject according to the comparison.
 4. The method as claimed in claim 1,wherein step (d) further comprises: creating a first maximum space boxfor the feature elements of the moving object and a second maximum spacebox for the matched feature elements of the reference object;calculating an initial iteration parameter according to positions of acenter point of the first maximum space box and a center point of thesecond maximum space box; obtaining an initial moving matrix of themoving object; and moving the moving object from the position of thecenter point of the feature elements of the moving object to theposition of the center point of the matching feature elements of thereference object, according to the initial moving matrix.
 5. The methodas claimed in claim 1, wherein step (e) further comprises: obtaining theinitial iteration parameter; calculating a value of an iterationfunction f(x); calculating a descent direction of the moving object at acurrent position, in response that the value of the iteration functionf(x) is not less than a preset minimum value FunX; moving the movingobject with a distance D at the descent direction, and calculating avalue of an iteration function f(x+1) after the movement, in responsethat the moving object has the descent direction; continuing to move themoving object with the distance D at the descent direction in responsethat the value of f(x+1) is less than the value of f(x), or calculatinga new descent direction of the moving object in response that the valueof f(x+1) is not less than the value of f(x); calculating a currentiteration parameter in response that the value of the iteration functionf(x) is less than FunX, or the moving object has no descent direction;and obtaining the moving-and-rotating matrix of the moving object.
 6. Anon-transitory storage medium storing a set of instructions, the set ofinstructions being executed by a processor of an electronic device, toperform a method comprising: (a) inputting a moving object and areference object; (b) acquiring triangle data of the moving object, andfitting feature elements of the moving object according to the triangledata; (c) determining feature elements of the reference object whichmatch the feature elements of the moving object; (d) moving the movingobject from a position of a center point of the feature elements of themoving object to a position of a center point of the matched featureelements of the reference object; (e) obtaining a moving-and-rotatingmatrix of the moving object according to Quasi-Newton methods; and (f)aligning the moving object and the reference object by moving androtating the moving object according to the moving-and-rotating matrix.7. The non-transitory storage medium as claimed in claim 6, wherein step(b) further comprises: extracting sides of triangles in the triangledata that are not shared by the triangles in the triangle data; readingpoints of the extracted sides; and fitting the points into the featureelements of the moving object.
 8. The non-transitory storage medium asclaimed in claim 6, wherein step (c) further comprises: reading afeature element list of the reference object from a storage unit of theelectronic device; comparing the feature elements of the moving objectand the feature elements of the reference object; and extracting featureelements of the reference object which match with the feature elementsof the moving object according to the comparison.
 9. The non-transitorystorage medium as claimed in claim 6, wherein step (d) furthercomprises: creating a first maximum space box for the feature elementsof the moving object and a second maximum space box for the matchedfeature elements of the reference object; calculating an initialiteration parameter according to positions of a center point of thefirst maximum space box and a center point of the second maximum spacebox; obtaining an initial moving matrix of the moving object; and movingthe moving object from the position of the center point of the featureelements of the moving object to the position of the center point of thematching feature elements of the reference object, according to theinitial moving matrix.
 10. The non-transitory storage medium as claimedin claim 6, wherein step (e) further comprises: obtaining the initialiteration parameter; calculating a value of an iteration function f(x);calculating a descent direction of the moving object at a currentposition, in response that the value of the iteration function f(x) isnot less than a preset minimum value FunX; moving the moving object witha distance D at the descent direction, and calculating a value of aniteration function f(x+1) after the movement, in response that themoving object has the descent direction; continuing to move the movingobject with the distance D at the descent direction in response that thevalue of f(x+1) is less than the value of f(x), or calculating a newdescent direction of the moving object in response that the value off(x+1) is not less than the value of f(x); calculating a currentiteration parameter in response that the value of the iteration functionf(x) is less than FunX, or the moving object has no descent direction;and obtaining the moving-and-rotating matrix of the moving object. 11.An electronic device electrically connected to a test device, theelectronic device comprising: a storage unit; at least one processor;one or more programs that are stored in the storage unit and areexecuted by the at least one processor, the one or more programscomprising: an input module that inputs a moving object and a referenceobject; a fitting module that acquires triangle data of the movingobject, and fits feature elements of the moving object according to thetriangle data; a match module that determines feature elements of thereference object which match the feature elements of the moving object;a position module that moves the moving object from a position of acenter point of the feature elements of the moving object to a positionof a center point of the matched feature elements of the referenceobject; an iteration module that obtains a moving-and-rotating matrix ofthe moving object according to Quasi-Newton methods; and a rotationmodule that aligns the moving object and the reference object by movingand rotating the moving object according to the moving-and-rotatingmatrix.
 12. The electronic device as claimed in claim 11, wherein thefitting module further: extracts sides of triangles in the triangle datathat are not shared by the triangles in the triangle data; reads pointsof the extracted sides; and fits the points into the feature elements ofthe moving object.
 13. The electronic device as claimed in claim 11,wherein the match module further: reads a feature element list of thereference object from the storage unit; compares the feature elements ofthe moving object and the feature elements of the reference object; andextracts feature elements of the reference object which match with thefeature elements of the moving object according to the comparison. 14.The electronic device as claimed in claim 11, wherein the positionmodule further: creates a first maximum space box for the featureelements of the moving object and a second maximum space box for thematched feature elements of the reference object; calculates an initialiteration parameter according to positions of a center point of thefirst maximum space box and a center point of the second maximum spacebox; obtains an initial moving matrix of the moving object; and movesthe moving object from the position of the center point of the featureelements of the moving object to the position of the center point of thematching feature elements of the reference object, according to theinitial moving matrix.
 15. The electronic device as claimed in claim 11,wherein the iteration module further: obtains the initial iterationparameter; calculates a value of an iteration function f(x); calculatesa descent direction of the moving object at a current position, inresponse that the value of the iteration function f(x) is not less thana preset minimum value FunX; moves the moving object with a distance Dat the descent direction, and calculates a value of an iterationfunction f(x+1) after the movement, in response that the moving objecthas the descent direction; continues to move the moving object with thedistance D at the descent direction in response that the value of f(x+1)is less than the value of f(x), or calculates a new descent direction ofthe moving object in response that the value of f(x+1) is not less thanthe value of f(x); calculates a current iteration parameter in responsethat the value of the iteration function f(x) is less than FunX, or themoving object has no descent direction; and obtains the moving-androtating-matrix of the moving object.